Jayme Augusto Bertelli, Paulo Roberto Kechele, Marcos Antonio Santos, Hamilton Duarte and Marcos Flávio Ghizoni
Grafting or nerve transfers to the axillary nerve have been performed using a deltopectoral approach and/or a posterior arm approach. In this report, the surgical anatomy of the axillary nerve was studied with the goal of repairing the nerve through an axillary access.
The axillary nerve was bilaterally dissected in 10 embalmed cadavers to study its variations. Three patients with axillary nerve injuries then underwent surgical repair through an axillary access; the axillary nerve was repaired by transfer of the triceps long head motor branch.
At the lateral margin of the subscapularis muscle, the axillary nerve was found in the center of a triangle bounded medially by the subscapular artery, laterally by the latissimus dorsi tendon, and cephalad by the posterior circumflex humeral artery. At the entrance of the quadrangular space, the axillary nerve divisions were loosely connected to each other, and could be clearly separated and correctly identified. Surgery for the axillary nerve repair through the axillary access was straightforward. Eighteen months after surgery, all three patients had recovered deltoid strength to a score of M4 on the Medical Research Council scale and had improved abduction strength by 50%. No deficit was evident in elbow extension.
The axillary nerve and its branches can be safely dissected and repaired by triceps motor nerve transfer through an axillary access.
Jayme Augusto Bertelli, Paulo Roberto Kechele, Marcos Antonio Santos, Bruno Adler Maccagnan Pinheiro Besen and Hamilton Duarte
In C7–T1 palsies of the brachial plexus, shoulder and elbow function is preserved, but finger motion is absent. Finger flexion has been reconstructed using tendon or nerve transfers. Finger extension has been restored ineffectively by attaching the extensor tendons to the distal side of the dorsal radius (that is, tenodesis). In these types of nerve palsy, supinator muscle function is preserved because innervation stems from the C-6 root. In the present study, the authors investigated the anatomy and the feasibility of transferring the supinator motor branches to the posterior interosseous nerve. Sacrifice of the supinator motor branches does not abolish supination because biceps muscle function is preserved in lower-type injuries of the brachial plexus.
The posterior interosseous nerve was dissected in 20 formalin-fixed forearms. Through posterior forearm access, the posterior interosseous nerve and its motor branches to the supinator muscle were dissected. Specimens were removed for histological study.
In the vicinity of the supinator muscle's proximal margin (that is, the Frohse arcade), 2 nerve branches arose laterally and medially from the posterior interosseous nerve to innervate the superficial and deep heads of the supinator muscle, respectively. The supinator motor nerves, when divided, could be coapted directly to the posterior interosseous nerve. The number of myelinated fibers in the supinator motor branches corresponded to 70% that of the posterior interosseous nerve.
The supinator motor nerves can be transferred directly to the posterior interosseous nerve to restore thumb and finger extension in patients with C7–T1 brachial plexus lesions.